How do you deal with stress in the workplace?

Ask for help? I have been in these situation before and my biggest mistake was to continually say yes to people and not communicate with them or team colleagues about how much work i had going on. At least if you tell people, they may offer to help, or at the least they will not volunteer you for more work, until you get some cleared. At worst ask your manager can he delegate someone to help you fo even a day or so. Every liitle bit helps. and we are all human, no harm it admiting you are struggling, it better than having a job half done and paying the conquences later!